Earphone with noise reduction

An earphone adapted to provide an acoustic output signal to an ear of a wearer in dependence on an earphone audio signal and further adapted to be arranged on the wearer's head in an operating position such that a front cavity between the head and the earphone is separated from ambient space, the earphone comprising:

• a housing having a wall separating a rear cavity having an acoustic compliance from the front cavity and from ambient space;
• an ear cushion arranged and adapted to attenuate acoustic signals entering the front cavity from ambient space when the earphone is in the operating position;
• a first diaphragm reciprocatably suspended across a first through hole in the housing wall between the front cavity and the rear cavity and adapted to be actively driven to provide at least a portion of the acoustic output signal;
• and
• a second diaphragm reciprocatably suspended across a second through hole in the housing wall between the rear cavity and ambient space such that the second diaphragm and the rear cavity constitute an acoustic resonant system with an acoustic resonance at a resonance frequency,
• characterized in that:
• and wherein
• the acoustic resonant system is configured such that said resonance frequency is below 500 Hz
• and further comprising a dampener adapted to dampen reciprocation of the second diaphragm at said resonance frequency while allowing the second diaphragm to reciprocate at frequencies below said resonance frequency.

A wearable earphone adapted to provide an acoustic output signal to an ear of a wearer in response to an earphone audio signal, where the earphone, in an operating position such that a front cavity between the wearer's head and the earphone is substantially acoustically separated from ambient space the earphone comprising:

• a housing having a wall separating a rear cavity having an acoustic compliance from the front cavity and from ambient space;
• an ear cushion arranged and adapted to attenuate acoustic signals entering the front cavity from ambient space when the earphone is in the operating position;
• a first diaphragm reciprocatably suspended across a first through hole in the housing wall between the front cavity and the rear cavity and adapted to be actively driven to provide at least a portion of the acoustic output signal;
• and
• a second diaphragm reciprocatably suspended across a second through hole in the housing wall between the rear cavity and ambient space such that the second diaphragm and the rear cavity constitute an acoustic resonant system with an acoustic resonance at a resonance frequency;
• wherein the second diaphragm is mechanically connected to a driving coil suspended in a magnetic field and includes a dampener including an electronic dampening circuit electrically connected to the driving coil.

A method of reducing ambient noise to a wearer of a wearable earphone capable of providing an acoustic output signal to an ear of the wearer in response to an earphone audio signal, where a front cavity between the head and the earphone is substantially acoustically isolated from ambient space the earphone comprising steps of:

• forming an acoustic chamber in a housing having a front and rear cavity with a wall separating the cavities;
• locating an ear cushion to attenuate acoustic signals entering the front cavity from ambient space when the earphone is in the operating position;
• suspending a first diaphragm reciprocatably across said first through hole in the separating wall,
• actively driving at least a portion of the acoustic output signal;
• creating a second through hole in the housing wall between the rear cavity and ambient space;
• suspending a second diaphragm reciprocatably across a second through hole in the housing wall between the rear cavity and ambient space such that the second diaphragm and the rear cavity constitute an acoustic resonant system with an acoustic resonance at a resonance frequency;
• mechanically connecting the second diaphragm to a driving coil suspended in a magnetic field;
• and
• electrically connecting the dampener to an electronic dampening circuit electrically connected to said driving coil.